Process of making fast-gray prints, &amp;c.



GADIEN'I ENGI, OF BASED, SWITZERLAND,

ASSIGNOR TO SOCIETY OF CHEMICAL PROCESS OF MAKING FAST-GRAY PRINTS, 8w.

No Drawing.

Specification of Letters Patent.

Patented Apr. 5, 1910.

Application filed September 20, 1905. Serial No. 518.494.

To all whom it may concern:

Be it known that l, GADIEN'r ENG], a citizen of the Swiss Republic, and resident of Basel. 'Sxvitzerlaml, have invented a new and useful Process for Obtaining Fast-Gray Prints and Vat Dycings, of which the fol-- lowing is a full, complete, and exact specitl' cation.

According to the United States Letters Patent No. 848356 dated March 26, 1907, vat dyestuffs, which dye vegetable and animal fibers violet to blue tints, are obtained by treating with halogen the dyestuif of the constitution resulting from the condensation of equal molecular proportions of 3-oxy-l-thionaphthcnc and alpha-isatin-anilid or alpha-isntin-chlorid. I have now found that certain of these dyestufl's, namely the mono-halogen derivatives, are also applicable for producing valuable gray tints. For this purpose, the direct blue prints and vat dyeings obtained by means of such mono-halogen derivatives are treated with hot baths, for instance hot water, with or without addition of soap, alkali, acid, a neutral or an acid salt, or even a bichromate, according to the nature of the fiber (cotton or wool) the blue color of the prints and dyeings becomes a pure greenish-gray, which is dis tinguished by its admirable fastness to washing, light and chlorin. The gray tints produced on wool are quite fast to milling. Moreover, these gray dyeings have the remarkable advantage that in artificial light they appear greenish.

The following example illustrates the invention: 20 kilos of cotton yarn, which have been dyed in the usual manner in a hydro sultite vat containing 2 grams of a monobromo derivative or a monochlor derivative of the dycstuif of the constitution per liter, are oxidized by exposure to air, washed with cold water and then treated for half an hour at .90 C. with water or a soda. and soap solution, containing, say, 5 grams of soda and 5 grams of soap per liter. The goods are then washed and. dried.

The process is the same, when printed goods are to be treated.

The same result may obviously be attained if, instead of the 1nonohalo;;cn substitution products obtained by directly halogcnizing the condensation products of oxythiona )htheme and alpha-isa'tin-anilid or alp iaisatiirclilorid, there are used the dycstuils made synthetically, that is to say, by condensing mono-halogenderivatives of alphaisatin-anilid or alpha-isatin-chhnid with oxythionaphthcne.

If the dyestuffs in question are used in combination with other-suitable vat dyestuffs. such as cibaheliotrope (tetralu'omindirubin),.any desired gray tints are obtainable of absolute fastness by the foregoing procedure.

The herein described process for obtaining fast gray prints and vat dyeings, which consists in dyeing or printing fabrics with ,inono-halogen derivatives of the dyestutf of and subjecting said fabrics to a hot bath In witness whereof, I have hereunto signed my name in the presence of two sol scribing witnesses.

GADII'INT ENG l.

\Vitnesses GEO. GTFFORD, Auaxn Rrr'rnn. 

